Well, here's AHD:

also sel·vedge
NOUN: 1a. The edge of a fabric that is woven so that it will not fray or ravel. b. An ornamental fringe at either end of an Oriental rug. 2. The edge plate of a lock that has a slot for a bolt.


...so at this point I am quite flummoxed. I do like that 'edge plate' definition!

Oh, well. I suppose my grandmother must have been referring to 'salvages' based on this definition, also from AHD:

3. Something saved from destruction or waste and put to further use.